This invention relates to the art of roll grooving apparatus and, more particularly, to improvements in such apparatus relating to maintaining tracking between the grooving rolls and workpiece, stabilizing the apparatus during operation thereof and gauging the depth of rolled grooves.
The present invention finds particular utility in connection with portable roll grooving apparatus of the character removably mountable on a separate power drive unit including spaced apart and parallel support elements and a drive motor having a drive coupling for driving interconnection with a drive shaft of the roll grooving apparatus. Accordingly, the invention will be illustrated and described herein in connection with such a portable roll groover. However, it will be understood and appreciated from the disclosure herein that the invention is applicable to roll grooving apparatus integrally associated with a support and drive mechanism.
Roll grooving apparatus is of course well known, and generally, includes relatively displaceable first and second support components respectively rotatably supporting a driven grooving roll and an idler grooving roll between which a pipe to be grooved is interposed during a grooving operation. The grooving rolls are matingly contoured and, in this respect, the driven roll is provided with a peripheral groove and the idler roll is provided with a peripheral projection such that a pipe therebetween is provided with a peripheral groove upon relative rotation of the grooving rolls and relative radial displacement of the grooving rolls toward one another. Heretofore, the grooving roll axes have been vertically aligned and the displacement of the support components toward and away from one another is achieved either hydraulically or through the use of a threaded feed screw capable of accommodating a tool such as a wrench for manually rotating the feed screw. Often, the two support components are provided with an adjustable stop arrangement therebetween by which the relative displacement of the grooving rolls in the direction to form a groove in a workpiece is controlled to provide a depth of the groove appropriate for a given workpiece based on such factors as the diameter of the workpiece, the material of the workpiece and the wall thickness thereof Heretofore, a plurality of individual thickness gauges, or a gauge having multiple steps, have been tethered to the roll grooving apparatus, such as by a chain, for interposition between a stop member on one of the support components and a surface on the other support component to provide the necessary space therebetween for achieving the desired groove depth. In connection with performing a roll grooving operation with such apparatus, the grooving rolls are separated and a pipe to be grooved is inserted therebetween and held by the operator of the apparatus as the grooving rolls are displaced toward one another. The driven grooving roll imparts rotation to the pipe which in turn imparts rotation to the idler grooving roll and the latter is gradually advanced toward the driven roll to progressively form the peripheral groove in the pipe.
There are a number of problems and/or disadvantages associated with the structure and operation of roll grooving apparatus of the foregoing character. In this respect, for example, it is necessary for the pipe and grooving roll axes to be properly aligned during a roll grooving operation so that the track of the groove is transverse to the pipe axis. Misalignment at the beginning of an operation can cause the track of the groove to be spiral relative to the pipe axis whereby the pipe "walks" in the direction to axially separate the rolls and pipe. Accordingly, the operator must support the pipe in one hand while the idler grooving roll is advanced toward the driven grooving roll and, in connection with achieving the latter advancement through a feed screw mechanism, the operator must support the pipe with one hand and rotate the feed screw with the other, such as through use of a wrench. In any event, the combined pipe supporting and screw rotating requirements are awkward for the operator and difficult to achieve at the same time. Furthermore, the pipe grooving apparatus is generally supported on a bench or mounted on a stand elevated above a supporting surface such as a floor and, with a feed screw arrangement, the torque required to be applied to the vertical feed screw during a roll grooving operation is considerable and is applied by the operator by rotating the feed screw about a vertical axis which often results in the apparatus slipping relative to the underlying bench or floor or tipping relative thereto, especially when the directional force on the wrench is moving laterally outwardly of the drive shaft axis.
Another disadvantage resides in the fact that the operator, in adjusting the stop arrangement for a given roll grooving operation, must select the appropriate one of a plurality of individual thickness gauges, or the appropriate step of a single gauge, insert the latter in the space between the stop element and underlying support member, make the necessary adjustment and then remove the thickness gauge and return the latter to its storage location. Accordingly, the gauging procedure is time consuming, especially if the gauge or set of thickness gauges is not tethered or otherwise attached to the apparatus and the operator must put them in a pocket or otherwise store the set. Moreover, if the gauge or gauges become separated from the apparatus and/or misplaced, or lost, the operator must either rely upon guesswork in adjusting the stop arrangement or, alternatively, rely on a visual tracking of the groove depth to determine when the latter is appropriate for a given workpiece. While an experienced operator may be capable of performing an acceptable roll grooving operation in the foregoing manner, it is unlikely that an inexperienced operator could do so, whereby the potential for material loss through inappropriate grooving exists.